As local pesticide spray programs targeting adult mosquitoes with West Nile virus continue throughout the U.S., and with the new emergence of the Zika virus, it must be recognized that spray programs are of very limited efficacy. That is, spraying is NOT an effective or efficient way to prevent death or illness associated with insect-borne diseases.

The ineffectiveness of spraying to kill mosquitoes has to do in part with their life cycle, and in part with the mechanics of actually knocking down target insects — especially in urban environments. Spraying is typically done as ground spraying by trucks or as aerial application by aircraft.

The Zika virus, West Nile virus, and other mosquito-borne diseases are recognized public health threats. But given the limited efficacy of adulticidal sprays, or pesticides meant to target adult mosquitoes, it becomes even more important to understand the public health hazards associated with widespread pesticide exposure.

This has become especially timely given the current discussion over the potential use of DDT to combat the Zika virus (see Zika virus: Is DDT an option, published on CNN.com). Researchers have linked DDT exposure to impacts on fertility, immunity, hormones, and brain development; the pesticides most commonly used in the U.S. to target mosquitoes are neurotoxic, and have been linked to cancer and other illnesses. People with compromised immune systems, chemically sensitive people, pregnant women, and children with respiratory problems, such as asthma, are particularly vulnerable to these pesticides and will suffer disproportionately from exposure.

Beyond Pesticides has reached out to the Environmental Protection Agency (EPA) with concerns about the use of insecticides, such as naled (including its degradation product dichlorvos [DDVP]) and synthetic pyrethroids, to combat Zika and other mosquito-borne diseases. You can read our letter to EPA here, and EPA's response here.

If you are concerned about the spraying of pesticides in your community or local environment, want a copy of Beyond Pesticides' organizing packet, or want to get involved in any way, please contact Beyond Pesticides at 1.202.543.5450.